This application proposes a new health services research training program with an emphasis on patient safety in the hospital setting, which aligns with the AHRQ mission to provide evidence that improves the quality, safety, and effectiveness of healthcare. The postdoctoral training program leverages the numerous resources available at Columbia University, including the Mailman School of Public Health and the Irving Center for Clinical and Translational Research (CTSA), as well as its affiliation with NewYork-Presbyterian/Columbia University Medical Center. The purpose of the training program is to provide clinician-researchers with the foundation and skills to become independent investigators in patient safety and health services research. The program offers a unique combination of formal research education, mentored research projects, and exposure to patient safety operations at a large academic medical center. Trainees will have the opportunity to work with a diverse and accomplished group of Columbia faculty with a proven track record of grant funding, interdisciplinary research collaboration, publication, and mentorship. Our Faculty Mentors represent a broad range of clinical and academic disciplines including General Medicine, Pediatrics, Behavioral Cardiology, Infectious Diseases, Psychiatry, Neurosurgery, Pathology, Biomedical Informatics, Nursing, Epidemiology, and Health Policy. Faculty Mentors have expertise and active research support in AHRQ-related focus areas including medical errors, medication safety, healthcare-associated infections, health informatics, quality measurement and outcomes, cost and cost-effectiveness, chronic disease epidemiology, and health disparities. This 2-year training program consists of four core training components: 1) Formal Research Education; 2) Mentored Research Projects; 3) Patient Safety Immersion; and 4) Bi-Weekly Research Seminars. All Trainees will earn a Master?s degree in Epidemiology or Patient Oriented Research from the Mailman School of Public Health. In addition, a distinctive core component of the program is the Patient Safety Immersion, consisting of a patient safety curriculum leading to the Certified Professional in Patient Safety (CPPS) credential and a Trainee-developed research project based on real-world patient safety hazards. Trainees will participate in Patient Safety operations at Columbia University Medical Center, including reviewing adverse event reports and attending root cause analyses. A total of 11 Trainees will be admitted to the program, all with a hospitalist career trajectory and a strong interest in patient safety and health services research. Candidates will be recruited from Columbia?s top-ranked clinical training programs and through a wide range of national recruitment strategies, with a particular focus on recruiting underrepresented groups. The program will be centered in the Department of Medicine/Division of General Medicine, which houses the Section of Hospital Medicine and a well-established Primary Care Research Fellowship along with existing infrastructure to support training activities.